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Bertini :: subPoint

subPoint -- This function evaluates a polynomial or matrix at a point.

Synopsis

Description

Evaluate f at a point.

i1 : R=CC[x,y,z]

o1 = R

o1 : PolynomialRing
i2 : f=z*x+y

o2 = x*z + y

o2 : R
i3 : subPoint(f,{x,y},{.1,.2})

o3 = .1z + .2

o3 : R
i4 : subPoint(f,{x,y,z},{.1,.2,.3},SpecifyVariables=>{y})

o4 = x*z + .2

o4 : R
i5 : R=CC_200[x,y,z]

o5 = R

o5 : PolynomialRing
i6 : f=z*x+y

o6 = x*z + y

o6 : R
i7 : subPoint(f,{x,y,z},{.1,.2,.3},SubIntoCC=>true)

o7 = .23

o7 : CC (of precision 53)
i8 : subPoint(f,{x,y,z},{.1234567890123456789012345678901234567890p200,
             0,1},SubIntoCC=>true,M2Precision=>200)

o8 = .123456789012345678901234567890123456789

o8 : CC (of precision 200)

Caveat

When SubIntoCC is set to true then unset variables will be set to zero or unexpected values.

Ways to use subPoint :

For the programmer

The object subPoint is a method function with options.